1. Field of the Invention
The present invention relates to a cleaning unit and method for removing foreign matters, e.g., dust, which stick onto a surface of a member to be cleaned.
2. Description of the Related Art
An example of an arrangement of a recording device of the type in which an image receiving sheet and a toner sheet are put, in this order, on a recording rotational drum in close contact manner, and the toner sheet on the drum is irradiated with laser light for exposure, is shown in FIG. 11. The recording apparatus incorporates an optical head 1 capable of emitting a plurality of laser beams and arranged to modulate and turn the laser beam on/off to conform to record data. The optical head 1 is able to move in parallel with the rotational axis. The recording apparatus further incorporates a recording rotational drum 2 having the outer surface to which a recording medium 3 is joined, the recording rotational drum 2 being rotatively supported.
The optical head 1 is placed on a movable stage 4 which is able to move in parallel with the recording rotational drum 2. The foregoing movement corresponds to sub-scanning direction when an image is formed. The rotational direction of the recording rotational drum 2 corresponds to the main scanning direction.
As is shown in FIG. 12, the recording medium 3 is composed of an image-receiving sheet 5 and a toner sheet 6.
The image-receiving sheet 5 incorporates a support member, a cushion layer and an image receiving layer formed sequentially from a position adjacent to the recording rotational drum 2. The toner sheet 6 incorporates a support member, a photo-thermo conversion layer and a toner layer formed sequentially from a position adjacent to the position from which the laser beam is applied (see FIG. 13). The image-receiving sheet 5 is joined to the recording rotational drum 2 such that the toner sheet 6 is laminated on the image-receiving sheet 5. The toner layer of the toner sheet 6 joined as described above faces the image-receiving sheet 5. When a laser beam is applied to the toner sheet 6 from a position opposite to the image-receiving sheet 5, the toner layer portion irradiated with the laser beam is transferred to the image receiving layer owing to heat.
The support member is made of a PET (polyethylene terephthalate) base, a TAC (triacetyl cellulose) base, a PEN (polyethylene naphthalate) base or the like which permits penetration of the laser beam. The photothermo-conversion layer is constituted by a material, such as carbon, black pigment, infrared-ray absorption pigment, a substance for absorbing a specific wavelength or the like which efficiently converts the laser energy into heat.
The toner layer includes toner sheets in KCMY. A toner sheet in gold, silver, brown, gray, orange or green is sometimes used.
The image receiving layer receives transferred toner. The cushion layer absorbs the stepped portion formed when toner is laminated into a plurality of layers and absorbs a stepped portion formed owing to dust.
As for detailed contents of the image-receiving sheet 5 and the toner sheet 6 serving as the recording medium 3, refer to JP-A-4-296594, JP-A-4-327982 and JP-A-4-327983 applied by the applicant of the present invention. As for an image recording apparatus incorporating the foregoing recording medium, refer to JP-A-6-275183 if necessary.
Description will now be performed about a step for laser recording in each of KCMY and a step for separating the toner sheet 6 from the image-receiving sheet 5 after the recording operation has been completed. When a laminating process is performed, the laminating step is performed before the laser recording step. Then, the steps will sequentially be described with reference to FIG. 12.
(1) The image-receiving sheet 5 is wound around the recording rotational drum 2;
(2) To perform a K step, K toner sheet 6 is wound on its image-receiving sheet 5;
(3) Laser beams are applied in accordance with K image and/or character data to perform recording;
(4) The K toner sheet 6 is separated from the image-receiving sheet 5 (K step is completed);
(5) Then, a C step is performed. That is, the C toner sheet is wound on its image-receiving sheet;
(6) Laser recording is performed with C data;
(7) Finally, the C toner sheet is separated from the image receiving sheet (the C step is completed);
(8) Then, a M step is performed. That is, a M toner sheet is wound on its image receiving sheet;
(9) Laser recording is performed with M data;
(10) The M toner sheet is separated from the image receiving sheet (the M step is completed);
(11) A Y step is performed. That is, a Y toner sheet is wound on its image receiving sheet;
(12) Laser recording is performed with Y data;
(13) Finally, the Y toner sheet is separated from the image receiving sheet (the Y step is completed):
(14) Thus, KCMY are adequately laminated on the image receiving sheet so that a required color image is formed; and
(15) The color image is transferred to the main paper.
When the laminating process is performed, the toner sheet is pressed by a pressing roller or a heated roller immediately before the laser recording operation for each color is performed. Thus, toner sheet is brought into hermetic contact with the image receiving sheet.
It is preferable that the recording speed in the foregoing recording step satisfies a range from 0.5 m/s to 50 m/s, more preferably 1 m/s to 16 m/s. The basic recording operation of the recording apparatus is performed as described above.
The foregoing recording apparatus sometimes encounters deterioration in the quality of a result of the recording operation owing to a foreign matter (an object) such as dust when foreign matter is allowed to adhere to the outer surface of the recording rotational drum.
When foreign matter X is present between the image-receiving sheet 5 and the surface of the recording rotational drum as shown in FIG. 13, the foreign matter X deforms or causes defective adhesion of the image-receiving sheet 5 and the toner sheet 6. Thus, the focal point of the recording laser beam L is deviated. When deviation of the position in the optical axis of the photo-thermo conversion layer of the toner sheet 6 is larger than an allowable value, a sufficiently high energy density cannot be obtained. Hence it follows that thinning of the image and/or reduction in the density occurs in the range indicated with an arrow C in the drawing. As a result, an annular missing of an image or a white image is undesirably formed.
Another problem arises in that heat cannot sufficiently be relieved from the support member of the image-receiving sheet 5 to the recording rotational drum. Therefore, the temperature of the contact portion between the image-receiving sheet 5 and the toner sheet 6 is raised as compared with the temperature which is realized when no dust X is present. Thus, the density of the image in the range indicated with symbol C shown in the drawing is sometimes raised.
In the foregoing case, the housing covering the apparatus is opened to manually clean the outer surface of the drum. When the foregoing operation is performed whenever contamination occurs, a great labor and time are required.
For the above background reasons, the present invention has an foreign matter to provide a cleaning unit and method which are capable of removing foreign matters sticking to a surface of a member to be cleaned by cleaning the member surface by a simple operation.
To achieve the above object, the present invention provides a first cleaning unit which is comprised of:
a cleaning head in which a solution applying portion for applying a cleaning solution to a member to be cleaned, and a foreign-matter scraping blade for scraping foreign matters on the surface of the member to be cleaned are arranged substantially parallel to a cleaning direction,
wherein the solution applying portion and the foreign-matter scraping blade of the cleaning head are simultaneously brought into slide contact with the member to be cleaned, and in a cleaning operation, the solution applying portion passes a point on the member to be cleaned before the foreign-matter scraping blade passes the point.
The cleaning unit is capable of removing the foreign matters sticking to the surface of the member to be cleaned in such a simple manner that a cleaning solution applied to the surface of the member to be cleaned by the solution applying portion is scraped from the surface of the member to be cleaned by the foreign-matter scraping blade.
A second cleaning unit of the invention is constructed such that the solution applying portion and the foreign-matter scraping blade are integrally mounted on a base member.
In the cleaning unit, the solution applying portion and the foreign-matter scraping blade are integrally mounted on a base member. With this feature, the surface of the member to be cleaned can be cleaned in such a simple manner that the base member is controlled so as to move close to and move apart from the surface of the member to be cleaned.
A third cleaning unit is constructed such that the solution applying portion is formed of a flexible material which may be impregnated with the cleaning solution.
In this cleaning unit, the solution applying portion is formed of a flexible material which may be impregnated with the cleaning solution. Therefore, the cleaning solution may stably and uniformly applied to the surface of the member to be cleaned without any damage of the surface.
A fourth cleaning unit of the invention is constructed such that the foreign-matter scraping blade consists of an elastic film, and a contact angle of the foreign-matter scraping blade to the surface of the member to be cleaned is smaller than 90xc2x0 at a position on the member surface located downstream region as viewed in the cleaning direction.
In the cleaning device, the elastic film is brought into contact with the surface of the member to be cleaned at a predetermined contact angle. Therefore, it satisfactorily scrapes the foreign matter of the surface of the member to be cleaned. As a result, the foreign matter is prevented from remaining on the surface of the member to be cleaned. A quality cleaning is consequently performed while being free from incomplete scraping.
In a fifth cleaning unit of the invention, the elastic film consists of a resin film.
In this cleaning unit, the elastic film consists of an elastic resin film made of a PET or the like. Accordingly, in the scraping operation, the elastic film is brought into contact with the surface of the member to be cleaned, so that it is bent. Because of this bending, it is prevented that a gap is formed between the surface of the member to be cleaned and the foreign-matter scraping blade. This accrues to elimination of irregular scraping.
In a sixth cleaning unit, a plurality of foreign-matter scraping blades is linearly arrayed in the cleaning direction.
In this cleaning unit, the plurality of foreign-matter scraping blades is thus linearly arrayed in the cleaning direction. This feature successfully enhances the scraping effect and the foreign matter removal effect.
In a seventh cleaning unit, the member to be cleaned is a rotary body, and the cleaning head is arranged such that the solution applying portion is disposed downstream as viewed in the rotational direction of the member to be cleaned, the foreign-matter scraping blade is disposed upstream, and the cleaning head is substantially fixed in the rotational direction of the member to be cleaned.
In this cleaning unit, the solution applying portion and the foreign-matter scraping blade, respectively, are disposed downstream and upstream as viewed in the rotational direction of the member to be cleaned as a rotary body so that the solution applying portion and the foreign-matter scraping blade are substantially fixed in the rotational direction of the member to be cleaned. With this arrangement, when the member to be cleaned is rotated, the cleaning solution is applied to the surface of the member to be cleaned by the solution applying portion, and the cleaning solution applied is scraped off with the foreign-matter scraping blade. As a result, the foreign matter is removed from the surface of the member to be cleaned.
In an eighth cleaning unit, the cleaning head is supported in a state that it is movable in the rotation axis direction of the member to be cleaned as a rotary body.
In this cleaning unit, the cleaning head is supported in a state that it is movable in the rotation axis direction of the member to be cleaned as a rotary body. Therefore, the cleaning head is movable to a desired position on the surface of the member to be cleaned. The entire surface of the member to be cleaned is cleaned.
A ninth cleaning unit is constructed such that the cleaning head is supported while permitting the head to move close to and move apart from the member to be cleaned, whereby the surface of the member to be cleaned may partially be cleaned.
In this cleaning unit, the cleaning head is supported while permitting the head to move close to and move apart from the member to be cleaned. Therefore, the cleaning head may selectively be brought into contact with only the cleaning required portions on the surface of the member to be cleaned. This feature enables the cleaning to be localized in execution. Therefore, in particular when a location having foreign matters is known, the cleaning is efficiently performed.
In a tenth cleaning unit, the cleaning head is constructed such that the foreign-matter scraping blades are disposed on both sides of the solution applying portion as viewed in the cleaning direction, or on both sides of a plurality of solution applying portions linearly arrayed in the cleaning direction.
As just mentioned, in this cleaning unit, the foreign-matter scraping blades are disposed on both sides of the solution applying portion as viewed in the cleaning direction, or on both sides of a plurality of solution applying portions linearly arrayed in the cleaning direction. With this feature, in the forward and/or backward cleaning directions, the foreign-matter scraping blades are brought into slide contact with the surface of the member to be cleaned after the solution applying portion is brought into slide contact with the same. Therefore, the cleaning unit is capable of cleaning the surface of the member to be cleaned in both the forward and backward directions. The cleaning unit more efficiently cleans the surface of the member to be cleaned.
In an eleventh cleaning unit, the cleaning head is constructed such that the solution applying portions are disposed on both sides of the foreign-matter scraping blade as viewed in the cleaning direction, and the cleaning head includes a mechanism to detach, during the cleaning operation, the solution applying portion located downstream as viewed in the cleaning direction from the surface of the member to be cleaned.
In this cleaning unit, the solution applying portions are disposed on both sides of the foreign-matter scraping blade as viewed in the cleaning direction, and during the cleaning operation, the solution applying portion located downstream as viewed in the cleaning direction is detached from the surface of the member to be cleaned. With this feature, in the forward and/or backward cleaning directions, the foreign-matter scraping blade is brought into slide contact with the surface of the member to be cleaned after the solution applying portion is brought into slide contact with the same. Therefore, the cleaning unit is capable of cleaning the surface of the member to be cleaned in both the forward and backward directions. The cleaning unit more efficiently cleans the member to be cleaned.
A first cleaning method is a cleaning method for removing foreign matters sticking onto the surface of the member to be cleaned by using the seventh cleaning unit. In the cleaning method, the surface of the member to be cleaned is cleaned by rotating the member to be cleaned when the cleaning head is in slide contact with the member to be cleaned.
When this cleaning method is used, the member to be cleaned may be cleaned by rotating the member to be cleaned in a state that the cleaning head is in slide contact with the member to be cleaned. Therefore, the cleaning process may be completed for much shorter time.
A second cleaning method is a cleaning method for removing foreign matters sticking to the surface of the member to be cleaned by using the ninth cleaning unit. In the cleaning method, the cleaning head is positioned to a foreign-matter sticking location or therearound on the surface of the member to be cleaned in a manner that the member to be cleaned is rotated in the rotational direction while at the same time the cleaning head is moved in the axial direction of the member to be cleaned. Thereafter, the member to be cleaned is stopped in its rotation in the rotational direction, and in this state, the cleaning head is reciprocated several times in the axial direction, thereby effecting the cleaning of the surface of the member to be cleaned.
When the second cleaning method is used, the surface of the member to be cleaned may locally be cleaned by such a simple method that the cleaning head is positioned to a foreign-matter sticking location or therearound on the surface of the member to be cleaned, and in a state that the member to be cleaned is stopped in its rotation in the rotational direction, the cleaning head is reciprocated several times in the axial direction.